Calculating device



March 4, 1958 G. 1.. HALL 2,825,505

CALCULATING DEVICE Filed Nov. 1, 1954' IN V EN TOR. I 60 00 I, 15 41.4

United States Patent CALCULATING DEVICE Gordon L. Hall, Los Angeles, Calif. Application November 1, 1954, Serial No. 465,985 2 Claims. (Cl. 235-78) This invention relates generally to calculating apparatus and particularly discloses a novel light-weight, pocketsize device of this character especially adapted for the adding or subtraction of numbers such as fractions.

It is a common observation that the manipulation of fractions, where a plurality of such fractions of differing denominators must be added or subtracted, frequently gives rise to delay and error. Thus, in working with blueprints or other pictorial representations of physical structures whereon dimensions are indicated in fractions of an inch, such fractions may be expressed with denominators of 2, 4, 8, 16, 32 and 64. One using a print of this character may have occasion to add and /2 and subtract therefrom Although presenting no difiicult problem of theory, nevertheless it has been found that as a practical matter such a computation is unreasonably slow and subject to mistake.

The present invention meets the above need and in its simplest form includes a pair of relatively rotatable members, one of smaller diameter than and overlying the other, resembling in general construction a conventional circular slide rule. The upper member is preferably transparent, and both members may be if desired. A series of indicia, preferably 64 in number when lengths in fractions of an inch are to be computed, is disposed circumferentially on the larger of the two members immediately outside the periphery of the smaller. The device includes detent means adapted to yieldingly retain the two relatively movable members in a selected one of a plurality of discrete positions corresponding to the spacing of the indicia. A series of deformations may be included on the upper face of the upper member, or dial, to facilitate accurate rotation of the dial through a selected arc, such rotation being accomplished for example by a means of a stylus, the end of a pencil or similar object having a fairly sharp point.

A particular feature of the present invention resides in the provision of means for summing complete revolutions of the dial relative to the larger of the two members, or base. In the preferred form hereinafter shown and described, such means include a radial groove formed in the upper face of the base, a plurality of recessed grooves formed on the lower face of the dial and concentric therewith, transversely disposed transfer grooves formed in the lower face of the dial and communicating each of the concentric grooves with an adjacent concentric groove. An indicating member in the form of a movable element is slidably housed in the radial groove and its position longitudinally thereof is determined by its engagement with one of the grooves formed in the dial. The position of the movable member, radially of the base, may be observed by the user and, by reference to scalar indicia adjacent the radial groove, furnishes an immediate visual indication of the whole number of revolutions made by the dial relative to the base. Both the base and dial are made of rigid lightweight sheet material such as plastic, and the entire instrument may be carried in the user's pocket.

It is therefore, an object of this invention to disclose a novel calculating device particularly adapted for the adding or subtracting of proper and improper fractions.

Another object of the invention is to provide a device having the above characteristics which is small in size and may be carried in the users pocket.

A further purpose of the invention is to provide a device of the above nature including novel indicating means for summing revolutions of one member relative to another.

A further object of the invention is to provide a device of the above character which is rugged and reliable in operation and yet light in weight and inexpensive to manufacture.

Another object is to provide a calculating device including two relatively rotatable disc members and detent means for yieldingly urging the members into one of a plurality of discrete relative positions.

These and other and allied objects of the invention will become clear to those skilled in the art from a reading of the following description of a preferred embodiment thereof, taken in connection with the accompanying drawing in which:

Fig. l is a top plan view of a device embodying my invention, the instrument being set with its index point and revolution counter or zero.

Fig. 2 is a fragmentary sectional view taken on line Il-II of Fig. 1 showing the base radial groove, the dial concentric grooves and the movable indicating member housed therein.

Fig. 3 is a fragmentary sectional view taken on lines III-III of Fig. I particularly showing a preferred form of yieldable detent means.

Fig. 4 is a fragmentary sectional view taken on line IVIV of Fig. 3 showing the circumferentially spaced recesses and protuberances of the dial.

Fig. 5 is a fragmentary plan view of a portion of the dial and base, the dial reading being midway between and zero.

Fig. 6 is a fragmentary view of a portion of the dial and base, the reading of the instrument being 1% a portion of the dial being broken away to show the radial groove and its scalar indicia more clearly.

Referring now in detail to the drawing and first to Figs. 1 and 2 thereof, a base member is indicated generally at 10 and has mounted thereon a circular dial indicated generally at 12 overlying a circular portion of base 10. The dial 12 is rotatably connected to the base 10 by suitable journal means indicated generally at 14 so that the dial 12 is concentric with the base 10. In the present illustration base 10 is generally circular in outline but it will be understood that this particular shape is not necessary and may be varied as desired. For example, the base 10 may be polygonal, such as rectangular, so that the upper surface of the base 10 not overlain by dial 12 is available for having imprinted thereon an advertising message, decimal equivalents of fractions, or other information. In any construction, the base member extends outwardly beyond the periphery of the circular dial 12 so that at least an annular portion 18 of the base is available for having circumferentially spaced indicia imprinted thereon. The base and dial are made of any suitable rigid sheet material having appreciable thickness, and at least the dial is transparent. The base may be of metal, or both may be made of plastic material.

Upon the upper surface of the annular portion 18 of the base just referred to, there is provided a circumferentially extending series of spaced indicia. In the present illustrative embodiment of the invention, designed for use in adding and subtracting fractional portions of an inch, there are 64 such equally spaced indicia commencing at zero at the top of the instrument as seen in Fig. 1, and continuing clockwise around to 63 and thence back to zero. The upper surface of the dial 12, immediately inside the outer circumference 20 of the dial, is provided with a series of deformations arcuately spaced about the periphery of dial 12'at intervals corresponding to the spacing of the indicia on the upper surface of base 1G. Thus there are 64 of the deformations 2 2. In the preferred form of the invention, the deformations take the form of recesses (see Fig. 2) extending downwardly only partially of the total thickness of the dial 12. One of the indicia 22, as indicated at 24,'is identified by suitable means such as a blackened rectangle surrounding this particular recess and'constituting an index point for dial 12 relative to base 10.

Detent means aredesirably included in the present invention in order to yieldably'retain the index point 24 of dial 12 in any desired angular position'relative to base 16. in the present embodiment, such detent means include a radially extending resilient arm indicated generally at 36 (see Fig. 3), having its inner end fixedly connected to the base 10 in a shallow recess in the upper surface of the base by suitable attachment means such as a rivet 32. The outer end of arm 30 extends into a relatively deeply recessed pocket 34 formed in the base 10. This outer end of arm 30 is resiliently biased upwardly and desirably includes an arcuate portion 36 convexed upwardly, arranged to be received in one of the spaces 38 existing between a series of downwardly projecting protuberances 40 formed on the lower face of the dial 12. Desirably the protuberances 40 are vertically aligned with recesses 22, but this is not necessary for satisfactory operation. A downwardly recessed groove 42 formed in the upper face of base 10 extends concentrically with the base 10 and serves to house the downward protuberances 40 formed on the dial 12. Thus the detent means including resilient arm 30 urges the dial 12 into one of 64 equally spaced discrete positions relative to base 10, but the resilience of arm 30 permits manual'or digital rotation of the dial relative to the base. In order to insure that the dial 12 is retained in snug sliding contact with the base 10 despite possible flexibility of the base and dial, there may be provided a member indicated generally at 50 (see Fig. 2) projecting upwardly from the upper surface of base 10 and including an inwardly extending lip or flange 52, arranged to overlie the outermost portion of dial 12. Thus the member 50 constitutes in effect a pocket or recess into which the outermost portion of the dial 12 is slidably received, and the lip 52 insures that the protuberances 40 are held in contact with the convex detent member 36 to accurately position the dial in a selected orientation relative to the base.

Means are provided for summing complete revolutions of the dial 12 relative to base 10. A groove indicated generally at 55 is formed in the upper surface of the base it), the groove extending radially of the base 10 beneath dial 12. A movable indicating member 56 here shown as a small spherical ball is received in the groove 55, in such a way that its upper portion extends outwardly of the groove and above the upper surface of the base 10. Means are incorporated in the lower surface of dial 12 by which to retain the movable indicator 56 in a desired position longitudinally of the groove 55 and to shift the indicator 56 by a predetermined amount radially of the base 10 each time the dial 12 makes a complete revolution relative to the base. Immediately adjacent radial groove 55 on the upper surface of base 10 is a series of spaced indicia in the form of numerals indicated generally at 58, and best seen in Fig. 6 where a portion of the dial 12 has been broken away to render the indicia 58 and groove 55 more easily visible. Indicia 58 include numerals O, 1, 2, 3, 4 and although it will be evident that more or fewer numerals might be included if desired.

The means previously referred to for retaining the movable indicator'56 in a desired position longitudinally of groove 55 and for moving the indicator along the 4 groove, include a plurality of concentric circular grooves formed in the lower surface of dial 12 overlying the length of radial groove 55, and a series of inclined transverse grooves communicating one of the concentric grooves with the next concentric grooves in radial sequence. The concentric grooves referred to are indicated at 6%), 62, 64-, 66, 68 and 70 (see Fig. 2). The transverse grooves are indicated (see Fig. 1) at 61, 63, 65, 67 and 69, the last named transverse groove communicating with the innermost concentric groove Each of the transverse grooves extends between and communicates with the circular grooves identified by reference characters one greater and one less than the transverse groove. The outer concentric groove 6% terminates at 72 and the inner concentric groove terminates at 74.

It will now be seen that the transverse grooves just referred to are in substantial radial alignment with index point 24 and constitute in effect switching means by which to shift the movable indicator 56 longitudinally in radial groove 55. It will be further observed that such shift occurs as the index point 24 is moved clockwise from the indicium 63 (meaning inch) to zero. This is illustrated in Fig. 5 where the parts are shown'approximately midway between the two points just mentioned. The movable indicator 56 is similarly midway between the digit 0 and the digit 1 in the radially disposed indicia 58.

The operation of the present device will in majorrespects be. understood from the foregoing description. 'When it is desired to add a number of fractional parts of an inch, or any other numbers for which the annular indicia on the base 16 are designed, the device is first set to the position shown in Fig. 1. Now the dial 12 is rotated clockwise, as by a stylus or the like inserted in a recess 22, until index point 24 is opposite the first of the fractions to be added. Next the stylus is inserted in the uppermost recess 22 (opposite 0 of the indicia 18) and the dial is thereby rotated until the stylus is opposite the second fraction to be added. The index point-24 is now opposite the sum of the two fractions. :This process is repeated for each fraction to be. added,- the index point 24 always indicating the total of the fractions added. It is to be especially noted that the movable indicator 56, has, so long as dial 12 does not make a complete revolution, been maintained in stationary position radially of the instrument, by reason of being engaged by the outermost circular groove 66.

When the index point 24 has been moved to the'annular indiciu-m 63 and is then continued in clockwise direction, the movable indicator 56, which has up to now been opposite the digit 0 of the indicia 58, enters the transverse groove 61 and is thereby moved radially downwardly as seen in the figures toward the circular groove 62. In Fig. 5 is shown the position'of the parts midway between a reading of and zero. As the dial 12 continues its clockwise rotation, as for example,to the position shown in Fig. 6, the movable indicator 56 completes its movement in transverse or inclined groove 61 and is now engaged by circular groove 62 and is opposite the digit 1 of indicia 58. Thus the reading of the instrument as shown in Fig. 6 is 1% It will be readly apparent that because of the transverse grooves 61, 63, 65, 67 and 69, the movable object 56 is switched from one of the concentric grooves to the adjacent con centric groove each time the dial 12 is caused to make one revolution relative to base 10. The position of indicator 56 relative to indicia 58 may be readily observed by the user since dial 12 is transparent.

Subtracton of fractions by means of the present invention is accomplished by rotating the dial 12 counterclockwise through an angle corresponding to the fraction to be subtracted, and it will be seen that the action of the transverse grooves 61, 63, 65, 67, 69 serves to move,

the indicator 56 one step radially outwardly each time the dial 12 is moved in a counterclockwise direction from the indicium "0 to the indicium "63 of the annular indicia 18 carried by base 10. In subtraction the device is first set to the minuend, and when the minuend is a mixed number or an improper fraction, care must be taken that the device is initially positioned with the indicator 56 opposite the proper digit of indicia 58. It will be noted that the detent means including upwardly biased resilient arm 30 and spaced protuberances 40 insure that the dial 12 tends always to come to rest with index point 24 in alignment with one of the annular indicia 18, so that errors and guesswork in reading the instrument are virtually completely eliminated.

Accordingly it will be seen that I have provided a useful device for rapid adding and subtracting of numerals which may be expressed as portions of rotating movement of one member relative to another and particularly applicable as herein shown and described to the adding and subtracting of fractions of an inch. It will be readily understood that by appropriate modification of the indicia carried on the upper annular surface of base It), the present device may be made to be suitable for adding or subtracting numerals having any other significance desired, such as days of the month, for example. Modifications and changes from the specific forms of the invention hereinabove shown and described will readily occur to those skilled in the art. All such modifications not departing from the spirit of the invention are intended to be embraced within the scope of the appended claims.

I claim:

1. A calculating device comprising: a base plate hearing equally spaced circularly arranged indicia on its upper surface; a circular dial rotatably mounted on the base plate for rotation in a plane parallel thereto, the circumference of the dial being inward of said indicia, the dial and base plate having generally fiat relatively slidable juxtaposed faces, one of said faces having a radial groove formed therein and the other face having formed therein a plurality of arcuate grooves concentric with said dial and transfer grooves connecting each arcuate groove with an adjacent arcuate groove; and an indicating element, said radial groove and the arcuate and transfer grooves cooperating to slidably house the indicating element between said faces, said dial being transparent and bearing second indicia thereon, whereby the position of the indiciating element along the radial groove may be visibly determined.

2. The invention as stated in claim 1 wherein said indicating element is spherical.

References Cited in the file of this patent UNITED STATES PATENTS 1,510,481 Koester Oct. 7, 1924 1,780,078 Hite Oct. 28, 1930 2,060,674 Hicks Nov. 10, 1936 

